25.3.12 Argp User Customization

The formatting of argp ‘--help’ output may be controlled to some
extent by a program’s users, by setting the ARGP_HELP_FMT
environment variable to a comma-separated list of tokens. Whitespace is
ignored:

‘dup-args’

‘no-dup-args’

These turn duplicate-argument-mode on or off. In duplicate
argument mode, if an option that accepts an argument has multiple names,
the argument is shown for each name. Otherwise, it is only shown for the
first long option. A note is subsequently printed so the user knows that
it applies to other names as well. The default is ‘no-dup-args’,
which is less consistent, but prettier.

‘dup-args-note’

‘no-dup-args-note’

These will enable or disable the note informing the user of suppressed
option argument duplication. The default is ‘dup-args-note’.